Image sensing unit mounted in an eyeball assembly separately from the camera unit

Abstract: An object of this invention is to provide an image recording unit, which can pivot an image recording unit main body having a photographing optical system, which includes at least a photographing lens and an image pickup element, like the behavior of an eyeball, can realize a compact camera as a whole, and can reduce noise. In order to achieve this object, an image recording unit of this invention includes an image recording unit main body which accommodates at least a photographing lens and photographing apparatus in a case, and has a spherical surface portion for defining a driving surface at least on the outer surface of the case, support means for rotatably supporting the image recording unit main body to have a crossing point of at least two orthogonal axes as a center of rotation of the spherical portion, and frictional driving apparatus for frictionally driving the image recording unit main body independently in arbitrary directions by a frictional force generated between the driving surface and the support mechanism.

Description: The present invention relates to an image recording unit which can pivot an image recording unit main body in the direction of an object to be photographed in a manner similar to the behaviour of an eyeball, and a camera having the image recording unit. As a conventional mechanism for changing the photographing direction of a camera, a system in which a camera main body is attached onto a rotary base (panhead), and the rotary base is motor-driven has been proposed. However, in the above-mentioned conventional mechanism for changing the photographing direction of the camera, a driving device for rotation is arranged outside the camera main body, resulting in a large structure. In this case, attainable size reduction of a device for fetching an image is limited. In particular, in order to assemble this device in a robot's eye (image input device), the conventional structure has a considerable limitation in size. Noise upon driving is not small in the conventional mechanism since a device for rotation is arranged outside the camera main body in the conventional mechanism. SUMMARY OF THE INVENTION The present invention has been made in consideration of the above situation, and has as a concern to provide an image recording unit, which pivots an image recording unit main body with a photographing optical system, which includes at least a photographing lens and an image pickup element, like the behaviour of an eyeball in place of rotating a camera itself to which the photographing optical system is attached, and which unit can make the camera compact as a whole, and can reduce noise. US patent No. US-A-4855838 discloses a remotely controlled tilt and pan television camera in which the camera unit is mounted on the inner of two gimbals which are rotated by respective motors. US patent No. US-A-4788596 discloses means for reducing the effect of vibration on an imaging device by controllably rotating a cylindrical body holding an optical imaging system. In accordance with the present invention there is provided an image recording unit as set out in claim 1. With the above arrangement, the image recording unit main body can be pivoted like the behaviour of an eyeball, and a photographing operation can be performed by pivoting only the image recording unit main body in an arbitrary direction. Since the driving operation of the image recording unit main body depends on frictional driving between the support means and the image recording unit, quiet and smooth pivotal motion can be attained. Furthermore, as compared to a conventional mechanism which pivots the entire camera using a panhead, since only the image recording unit main body is driven, the driving load is small, and power consumption can be saved. In addition, since the conventional mechanism using the panhead drives the entire heavy camera using a reduction mechanism, the output must be increased to increase the pivot speed, and it is difficult to stop the camera at a desired position due to a large moment of inertia. In contrast to this, since an object to be driven is the lightweight image recording unit main body, the pivot speed can be increased, and positioning precision can be improved. Furthermore, the image recording unit main body can be driven to have a crossing point of three orthogonal axes as a center. A camera according to the present invention is characterized by the following arrangement. That is, an image recording unit described in any one of appended claims 1 to 4 is attached to a camera main body. With this arrangement, a photographing operation can be performed by turning the image recording unit in an arbitrary direction without pivoting the camera itself. Other features and advantages besides those discussed above shall be apparent to those skilled in the art from the description of a preferred embodiment of the invention which follows. In the description, reference is made to accompanying drawings, which form a part hereof, and which illustrate an example of the invention. Such example, however, is not exhaustive of the various embodiments of the invention, and therefore reference is made to the claims which follow the description for determining the scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view showing the first embodiment of an image recording unit according to the present invention; Fig. 2 is a side sectional view of Fig. 1; Figs. 3A to 3E are views showing modifications of a spherical rotary unit fixing frame; Figs. 4A to 4D are views showing modifications of a spherical rotary unit; Fig. 5 is a block diagram showing an image recognition apparatus according to the second embodiment of the present invention; Fig. 6 is a block diagram showing an infrared ray image recognition apparatus according to the third embodiment of the present invention; Fig. 7 is a block diagram showing a stereoscopic image input apparatus according to the fourth embodiment of the present invention; Figs. 8A and 8B are respectively a block diagram and a schematic view showing a camera shake correction apparatus according to the fifth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments of the present invention will be described in detail hereinafter with reference to the accompanying drawings. (First Embodiment) Fig. 1 is a perspective view showing an image recording unit according to the first embodiment. Referring to Fig. 1, reference numeral 1 (1a and 1b) denotes piezoelectric elements for forming a traveling wave around the X-axis and a traveling wave around the Y-axis in a spherical rotary unit fixing frame 2 (to be described later) upon application of driving frequency voltages. When a driving frequency voltage is applied to the pair of piezoelectric elements 1a which are arranged to oppose each other in the horizontal direction, a traveling wave around the Y-axis is formed in the fixing frame 2. When a driving frequency voltage is applied to the pair of piezoelectric elements 1b which are arranged to oppose each other in the vertical direction, a traveling wave around the X-axis is formed in the fixing frame 2. These traveling waves cause the surface particles on the fixing frame 2 as an elastic member to make an elliptic motion, and frictionally drive a spherical rotary unit 5 (to be described later) which is in press contact with the formation surfaces of the traveling waves. In this embodiment, the traveling waves are formed by the two pairs of opposing piezoelectric elements 1a and 1b. Alternatively, the traveling wave may be formed by each piezoelectric element. More specifically, when a traveling wave is formed in a predetermined direction in a vibration elastic member attached to one piezoelectric element, frictional driving forces are generated at a total of four positions. Note that the principle of formation of the traveling wave is known to those who are skilled in the art, and a detailed description thereof will be omitted. When two standing waves having a 90° phase difference therebetween are formed by a piezoelectric element on a vibration elastic member, the surface particles on the vibration elastic member make an elliptic motion upon synthesis of the two standing waves. With this elliptic motion, a member which is in press contact with the vibration elastic member is frictionally driven. If frequency voltages which are in phase with each other are applied to the piezoelectric elements which form two standing waves, no elliptic motion is formed, only standing waves are formed, and the vibration elastic member and the other member are in press contact with each other at the peaks of the waves in a point contact manner. Reference numeral 2 denotes a spherical rotary unit fixing frame which fixes the piezoelectric vibration elements 1a and 1b, and also fixes the entire unit in the camera. The fixing frame 2 consists of, e.g., an elastic member such as a metal. In this embodiment, the piezoelectric elements 1 are provided to the spherical rotary unit fixing frame 2 to form traveling waves. Alternatively, piezoelectric elements for forming traveling waves may be provided to the spherical rotary unit 5 (to be described later). Reference numeral 3 denotes an optical lens which is used for attaining condensing, focusing, and zooming operations; 4, an image pickup element (CCD) for converting an image obtained via the optical lens 3 into an electrical signal; and 5, a spherical rotary unit which accommodates the optical lens 3 and the image pickup element 4 in a case. The spherical rotary unit 5 is rotatable about the X- and Y-axes by the traveling waves which are excited by the piezoelectric elements 1 and cause an elliptic motion in the rotary unit fixing frame 2, which is in press contact with the rotary unit 5. When in-phase frequency voltages are applied to the piezoelectric elements serving as a support axis of rotation (e.g., the piezoelectric elements arranged in the vertical direction when the unit is rotated about the Y-axis), since these piezoelectric elements do not form traveling waves, a point contact bearing is constituted at that portion, and the spherical rotary unit can be smoothly rotated. Reference numeral 6 denotes a direction sensor for detecting the rotational angle of the spherical rotary unit 5 with respect to the camera main body; and 7, 8, 9, and 10, an image signal line for sending image information from the image pickup element 4, a direction control signal line for sending information for driving the piezoelectric elements 1, a lens control signal line for controlling the optical lens 3, and a direction sensor signal line for sending information from the direction sensor 6, respectively. Fig. 2 is a side sectional view which is provided for the purpose of easy understanding of the structure of this embodiment. Referring to Fig. 2, reference numeral 11 denotes an image processing apparatus for reconstructing electric information from the image pickup element 4 as an image; 12, a direction controller for changing the direction of the spherical rotary unit 5 by driving the piezoelectric elements 1; and 13, a lens controller for controlling the focusing and zooming operations of the optical lens 3. The movement of the spherical rotary unit 5 is controlled while the rotational position of the spherical rotary unit 5 is confirmed by the direction sensor 6 and is constantly fed back to the direction controller 12. The operation of this embodiment will be described below. When the spherical rotary unit 5 faces the front side of the camera, since the fixing frame 2 to which the piezoelectric elements 1 are attached is in press contact with the spherical rotary unit 5, the spherical rotary unit 5 is fixed, i.e., in a lock state due to friction of the contact surfaces if no voltages are applied to the piezoelectric elements 1. More specifically, even when the camera main body vibrates, the relative direction of the spherical rotary unit 5 with respect to an object to be photographed is maintained. When the frame is to be panned in the horizontal direction (the spherical rotary unit 5 is rotated in the horizontal direction), driving frequency voltages are applied to the pair of right and left piezoelectric elements 1a. Then, an elliptic motion having an axis of rotation in the Y-axis direction is formed in the fixing frame 2 in the X-Z plane. With this elliptic motion, the spherical rotary unit 5 is rotated about the Y-axis in Fig. 1, and can photograph an object to be photographed in the right-and-left direction via the optical lens 3 and the image pickup element 4. When the frequency voltages applied to the piezoelectric elements 1 are stopped, the spherical rotary unit 5 is locked at a desired angle by the frictional force of the press contact surfaces. As a result, the direction of the spherical rotary unit 5 can be fixed, and the photographing direction can be fixed. Similarly, when the frame is to be panned in the vertical direction (the spherical rotary unit 5 is rotated in the vertical direction), driving frequency voltages are applied to the pair of upper and lower piezoelectric elements 1b. Then, an elliptic motion having an axis of rotation in the X-axis direction is formed in the fixing frame 2 in the Y-Z plane. With this elliptic motion, the spherical rotary unit 5 is rotated about the X-axis in Fig. 1, and can photograph an object to be photographed in the vertical direction via the optical lens 3 and the image pickup element 4. When the frequency voltages applied to the piezoelectric elements 1 are stopped, the spherical rotary unit 5 is locked at a desired angle by the frictional force of the press contact surfaces. As a result, the direction of the spherical rotary unit 5 can be fixed, and the photographing direction can be fixed. When the photographing direction is fixed and the frame is moved in a tilted direction (the spherical rotary unit 5 is rotated in a plane perpendicular to the Z-axis), voltages are applied to one or two pairs of the piezoelectric elements 1 in the vertical and horizontal directions to form elliptic motions having the Z-axis in Fig. 1 as a center in the same rotational direction on the driving surfaces of the piezoelectric elements 1. Thus, the spherical rotary unit 5 is rotated about the Z-axis in Fig. 1, and a tilted image can be photographed via the lens 3 and the image pickup element 4. When the frequency voltages applied to the piezoelectric elements 1 are stopped, the spherical rotary unit 5 is locked at a desired angle by the frictional force of the press contact surfaces, and a photographed image can be fixed. Furthermore, by combining the above-mentioned rotations, the frame can be oscillated in an arbitrary direction (the spherical rotary unit 5 can be rotated about an arbitrary axis). Note that the rotational moving amount of the spherical rotary unit 5 with respect to the camera main body can be confirmed by the direction sensor 6. In addition to the horizontal and vertical directions, the rotary unit 5 can be rotated in the tilted direction. Furthermore, by combining the horizontal and vertical rotations, the rotary unit 5 can be smoothly rotated in an arbitrary direction. By utilizing these features, the frame can be easily set by a remote control operation in a self-timer photographing mode of the camera without using a tripod or panhead. In addition, this image recording unit can be applied to a remote control operation of a monitor camera for crime prevention. Note that the rotary unit 5 need not have a perfect spherical shape, but only its rotation range need have a spherical shape. For example, in addition to the spherical shape shown in Fig. 3A, spherical shape + conical shape in Fig. 3B, spherical shape + planar shape in Fig. 3C, spherical shape + cylindrical shape in Fig. 3D, a type having a lens and an image pickup element outside a spherical unit in Fig. 3E, and the like are available. As the type of the spherical rotary unit fixing frame and the number and arrangement of piezoelectric elements, those shown in Figs. 4A to 4D may be used. As shown in Fig. 4A, a transparent spherical rotary unit fixing frame is adopted to widen the view field range photographed by the camera. As for the number and arrangement of piezoelectric elements, the piezoelectric elements may be arranged around the spherical rotary unit in a ring pattern, or a large number of piezoelectric elements may be arranged, as shown in Fig. 4B. Also, as shown in Fig. 4C, the piezoelectric elements may be arranged to form symmetrical pairs, or to be paired with rotors or low-frictional members. Furthermore, as shown in Fig. 4D, a driving operation may be realized by only one piezoelectric element, and the shape of the piezoelectric element such as a circular shape, ring shape, rectangular shape, polygonal shape, or the like may be selectively used depending on the rotational direction and the arrangement position. In place of the driving piezoelectric elements, a columnar ultrasonic wave motor or a normal electromagnetic motor may be used. In the following description up to the fifth embodiment, assume that the unit has a spherical shape, and two pairs of piezoelectric elements are fixed by a stripe-shaped frame to be shifted from each other by 90°. (Second Embodiment) Fig. 5 shows the second embodiment. In this embodiment, the first embodiment is applied to image processing. An electrical signal obtained by converting an image by the image pickup element 4 in the spherical rotary unit 5 is reconstructed as an image by the image processing apparatus 11, and the contents of the image are recognized by an image recognition apparatus 14. Depending on recognition methods, items such as shape, color, operation, change, and the like can be recognized. By feeding back information of the image recognition apparatus 14 to the direction controller 12, a required object to be photographed can be automatically selected and traced. In addition, the ON/OFF state of an image recording operation can be automatically switched. For example, when a person is selected and traced by a monitor camera for crime prevention, the image recognition apparatus 14 recognizes a moving object to catch the person as an object, so as to perform a zoom-up photographing operation of his or her face or to trace his or her action. (Third Embodiment) Fig. 6 shows the third embodiment. In this embodiment, the first embodiment is combined with various sensors. As the sensors, various sensors such as an infrared ray sensor, a temperature sensor, an ultrasonic wave sensor, and the like are available. In this embodiment, an example using an infrared ray sensor will be explained. Fig. 6 is a schematic diagram showing the arrangement in which an infrared ray sensor and an image processing apparatus are arranged in the first embodiment. Information from an infrared ray sensor 15 is recognized by an infrared ray sensor image recognition apparatus 16. Based on information from the infrared ray sensor 15, items such as shape, color, operation, change, and the like can be recognized. By feeding back information of the infrared ray sensor image recognition apparatus 16 to the direction controller 12, a required object to be photographed can be automatically selected and traced. Also, the ON/OFF operation of the camera can be automatically switched. For example, when a person in a dark place is selected and traced by a monitor camera for crime prevention, the infrared ray sensor image recognition apparatus 16 recognizes a moving object, and a lamp in the room is turned on to catch the person as an image, thus allowing a zoom-up photographing operation of his or her face or tracing his or her action. When another sensor such as an ultrasonic wave sensor, a temperature sensor, or the like is used, the person can be recognized in the same manner as described above. (Fourth Embodiment) Fig. 7 shows the fourth embodiment. In this embodiment, the first embodiment is applied to a stereoscopic image input apparatus for a robot or a virtual reality (VR) system. As shown in Fig. 7, two spherical rotary optical units 5 are assembled in a robot or a VR system as the right and left eyes. Information signals photographed by the two spherical rotary optical units 5 are reconstructed as an image by the image processing apparatus 11. At the same time, the image is supplied to the image recognition apparatus 14 to analyze the shape, color, and movement of an object to be photographed. The image recognition apparatus 14 supplies a feedback signal to the direction controller 12, so that the right and left spherical rotary optical units 5 photograph an identical object at the centers of the corresponding image pickup elements 4. With this processing, a stereoscopic image which a photographer would see in practice at that place can be realized in a virtual space via, e.g., a headmount display. When the focusing and zooming operations of the camera are performed in correspondence with the visual axis of a photographer, the reality of the image can be enhanced. If this two-eye system is used, the size and distance of an object to be photographed can be calculated on the basis of the focusing positions of the optical lenses and the rotational angles of the spherical rotary units. Furthermore, when the spherical rotary units are controlled, the visual axis (the movement of the eyeball of a man) of a photographer or observer may be detected by a visual axis detection apparatus 19, and the spherical rotary units can be rotated in the moving direction of the visual axis. With this arrangement, a natural camera movement, which reflects an operator's will can be realized without imposing an extra load on an operator. (Fifth Embodiment) Figs. 8A and 8B show the fifth embodiment. In this embodiment, the first embodiment is applied to a camera shake prevention system or an anti-vibration system of visual information of a moving robot. When a camera is held by hands or when a robot to which a camera is attached is working or moving, an image photographed by the camera blurs due to a vibration of the main body. The vibration of the camera or the robot main body is detected by a camera shake sensor 17 shown in Fig. 8A, and a camera shake information processing apparatus 18 analyzes the direction, amplitude, period, and the like of the vibration on the basis of the detected information, thereby calculating information for canceling the vibration. The calculated information is fed back to the direction controller 12 to rotate the spherical rotary optical unit, thereby suppressing an image blur. With this processing, as shown in Fig. 8B, even when the camera main body vibrates in the vertical and horizontal directions, the direction of the spherical rotary optical unit relative to an object to be photographed can be maintained. In a conventional camera shake prevention mechanism, image quality deteriorates due to area movement of electric information, tilt of a variangle prism, and the like. However, by utilizing this embodiment, high image quality can be assured. In each of the above embodiments, an optical image from the imaging lens is received by the image pickup element. Alternatively, a film may be arranged in place of the image pickup element to constitute a still camera. As described above, according to each of the above embodiments, the image recording unit main body can be pivoted like the behavior of an eyeball, and a photographing operation can be performed by pivoting only the image recording unit main body in an arbitrary direction. Since the driving operation of the image recording unit main body depends on frictional driving between the support means and the image recording unit, a quiet and smooth pivotal motion can be attained. Furthermore, as compared to a conventional mechanism which pivots the entire camera using a panhead, since only the image recording unit main body is driven, the driving load is small, and power consumption can be saved. In addition, since the conventional mechanism using the panhead drives the entire heavy camera using a reduction mechanism, the output must be increased to increase the pivot speed, and it is difficult to stop the camera at a desired position due to a large moment of inertia. In contrast to this, since an object to be driven is the lightweight image recording unit main body, the pivot speed can be increased, and positioning precision can be improved. Furthermore, the image recording unit main body can be driven to have a crossing point of three orthogonal axes as a center. Since the case itself to be rotated has a spherical shape as a whole, the image recording unit main body can be easily supported, and a free pivotal motion can be assured. The image recording unit main body can be pivoted in an arbitrary direction by a simple arrangement, i.e., by arranging electro-mechanical energy conversion elements for forming traveling waves such as piezoelectric elements on the driving surface or support means side. This driving method is very quiet, and guarantees a very small pivotal motion and realizes high-precision positioning. A compact, simple driving mechanism can be obtained. The photographing main body can be pivoted in a desired direction by feedback control, and high-speed, high-precision control can be realized with low power consumption. In addition, a photographing operation can be performed by turning the image recording unit in an arbitrary direction without pivoting the camera itself. The present invention is not limited to the above embodiments and various changes and modifications can be made within the scope of the present invention. Therefore, to apprise the public of the scope of the present invention the following claims are made.

Claims: An image recording unit comprising: an image recording unit main body (5) which accommodates an imaging lens (3) and either an image pickup means (CCD) or a film; and support means (2) for rotatably supporting said image recording unit main body; characterised in that said image recording unit main body has a substantially spherical outer surface and in that the unit further comprises first and second electromechanical energy conversion elements (1a, 1b) for generating travelling waves on application of a frequency signal, said first and second electro-mechanical energy conversion elements being arranged either on the outer surface of the image recording unit main body or on support surfaces of the support means which face the outer surface of the image recording unit main body, said first and second electro-mechanical energy conversion elements being adapted to generate the travelling waves around two orthogonal axis which intersect at the centre of rotation of the image recording unit main body so as an operation to rotate the image recording unit main body relative to said support means. A unit according to claim 1, further comprising detection means (6) for detecting the position of said image recording unit main body, and control means (12) for driving said first and second electro-mechanical energy conversion elements on the basis of information from said detection means. A unit as claimed in either one of claims 1 or 2, wherein said imaging lens is fixed in relation to said unit main body. A camera wherein an image recording unit described in any one of the preceding claims is attached to a camera main body.

Inventors: NISHIMURA HIROSHI, SAKAI RIKAKO, SAKATA OSAMU, YAMAGUCHI SAKIKO, NISHIMURA, HIROSHI, SAKAI, RIKAKO, SAKATA, OSAMU, YAMAGUCHI, SAKIKO, NISHIMURA, HIROSHI, C/O CANON KABUSHIKI KAISHA, SAKAI, RIKAKO, C/O CANON KABUSHIKI KAISHA, SAKATA, OSAMU, C/O CANON KABUSHIKI KAISHA, YAMAGUCHI, SAKIKO, C/O CANON KABUSHIKI KAISHA
Applicants: CANON KK, CANON KABUSHIKI KAISHA
Application year: 1994
Main classification: H04N5
IPC codes: G03B17, G02B7, H04N13, G03B5, H04N5, G03B15